The Effect of Climate on The Development of Brown Spot Disease (Curvularia oryzae) in Rice Plants

Department of Plant Protection, Faculty of Agriculture, Mulawarman University, Jl. Pasir Balengkong, Kampus Gunung Kelua, Samarinda 75119, East Kalimantan, Indonesia

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Abstract

Rice (Oryza sativa L.) is a major food commodity in Indonesia, whose productivity often declines due to brown spot disease caused by the fungus Curvularia oryzae. This disease spreads rapidly in humid climates and poses a serious threat to national food security. This study aims to analyze the effect of climatic factors air temperature, relative humidity, rainfall, light intensity, and wind speed on the development of brown spot disease in rice plants in two different locations, namely Pulau Atas Village and Lempake Village, Samarinda City. The research methods included observing climate factors in the field, identifying the morphology and microscopy of C. oryzae in the laboratory, and analyzing data using multiple linear regression and partial correlation to determine the dominant factors affecting disease intensity. The results showed that all climatic factors had a significant effect on disease development, with relative humidity and rainfall being the most dominant factors in accelerating infection and pathogen spread. Disease intensity in Pulau Atas ranged from 0.4 to 52.6%, while in Lempake it ranged from 0.5 to 45.9%, increasing with plant age and humid microclimate conditions. Microclimate differences between locations affect the rate of infection and disease severity. In conclusion, controlling brown spot disease in rice requires consideration of local climate dynamics as the basis for formulating agroclimate-based control strategies to maintain stable rice production.